Thermostatic mixing valve



Feb. 5, 1935. v.c:. BOYDSTON 1,939,909 THERMOSTATIC MIXING VALVE I Filed May 19, 1933 3 Sheets-Sheet 1 Q I'NVENTOR? I Feb. 5, 1935. I v. c. BOYDSTON v 1,989,909

7 THERMOSTATIC MIXING VALVE Filed May 19, 1955 5 Sheets-Sheet s INVEN TOR Mag Patented Feb. 5, 1935 a 1,9 9,909

. 1,9aaoo9 THERMOSTATIC Mime vnnvii' I Verne c. Boyaston; Seattle, Wash. Application May 1a, 1933; Serial No. 671,861 11 Claims. (Cl. 236'-'-12) My invention relates to improvements in ther- Fig. 10 is an enlarged sectional view of a thermostatic valves of the form known as water mixmostat taken on the line 10--10 of Fig. 6, illusing valves, in which water of low and high temtrating an alternative form of the bimetallic strip. perature from separate conduits is supplied to the Fig. 11 is a'sectional view of a thermostat, taken valve and a mixture of intermediate temperature n h lin -10 of Fig. 6, illustrating a further 5 may be delivered, and the object of my invention variation in form of the bim al c p. is to provide a valve device having means for con- My mp v thermostatic valve comprises trolling the proportional mixing of the supplied i 10 wh h is P v W h a pluraltiy 0f liquids so that the delivery temperature may be openings for con ect on Wit upp y a d v y l0 predetermined; that has convenient external conduits, h f wn a 8- P 0f diametrically 10 means for adjusting the delivery temperature; p e inlet p n gs 11 and 1 r hOt and Y that has self contained means for preventing the cold Water respectively, and P l of outlet circulation of liquid from one source of supply Openings 13 and 141501 delivery of p d Water- I into the conduit of the other source and vice versa; The Pu Of e two Outlet Opening S is to a that has simple and rugged operating mechanism, tate the Piping cfthe Valve in i st lation n 15 ,11 f hi mechanism is constructed and which it may be desiredtodeliver tempered water ranged to be attached to a cover part, easily septo both 5 shower head and a as Shown in arable from abase part designed to receive all F 2. r pipe connections, whereby said operating mech- The inlet op llccmmlmieates W a' yanism may be removed for access without disllndrice-i rlS through a-passage 17, said 20 turbing said pipe connections; t t has provision chamber being constricted at its rearward end to forrenewal of valve parts subject to wear; that form a Seat ball 19 and a d ball being is adapted to be so mounted that, with said cover Pressed age-inst Said Seat by a pr n 1- A cypart flush witha wall and said base part imbedded lindricel screen 23, p n a both enda is held therein, all piping connections will be concealed concentrically in chamber 15 by Seating in a 25 from the fr t i i well or w t Said Ease -t counterbore 23- -A in casing 10- and'counterbore relatively close to the face of a wall and said pipe 25 in 9' P Said plug being screwed into connections substantially flush therewith; and the threaded open end o chamber 15. Similarly, that is relatively compact in form and of symthe inlet 12 communicates w a chamber 16 metrical and pleasing wneamnca through a passage 18 having a seat for a ball 20 30 The e bj t 1 attainby t construction and and a spring 22 for said ball. A similar screen arra e t of parts shown in t drawings and 24 is seated in counterbores 24a and 26 of the eashereinafter more particularly-described. That 1118 10 and p 28 e pectively. The inside diwhi I el t be new 11 be pointed out in ameter of the said screens is sufficiently greater th l i U than the diameter of the said balls to provide 35 I th accompanying drawings: lateral guidance for the ballsand their springs. Fig, 1 i from; e1evaticn of y improved that- Adjacent the chambers 15 and 16 and concentric mostatic valve mounted on a side wall with the with the casing 10 is mm 29 .adapted piping connections exposed, 1 to receive a valve bushing 30; The bore 29 is UNITED s'rAres PATENT OFFICE Fig'. 2 is a side elevation. of the valve with the Provided with axially pa d, continuous, con- 40 rear or base part imbedded in the face of a wall centric gmoves and 33, cored machined d th piping concealed behind said n in said bore, each groove being provided with a Fig. 3 is an enlarged sectional elevation of the connecting passageway for the inlet outlet of complete valve taken on the line 3-3 of Fig.'1 water. Chamber 15 communicates with groove 31 v Fig. 4 is a sectional view of the rear or base through a Passage 34; chamber! with groove 33 45.

part ofthe casing taken on the line 4-4 of Fig. 3. through PaSSage 35; and the groove 32 has a Fig. 5 is an enlarged sectional view of therear' dlschaige Passage and 3 connecting with e or e part, taken on t line of chamber 3'7, as best shown m-Fig. 5. The outlet Fig. 6 is a rear view of the thermostatic motor. Openings 3 d 1 are n ct d t th r y .5 Figi'? is a front view of the cover with the ada p age 41' and said passa e is al o in con- 5 justing handle removed. nection with chamber 3'1 through a passage 42, Fig. 8 is a rear view of the adjusting handle. as best shown in Fig. 5. a Fig. 9-is an enlarged view of the valve, partly in The bushing 30, held in place in bore 29 by section, illustrating a means of connection with its forced fit therein, is provided with axially I aconnecting rod. 1 v spaced grooves 43 and 44 formed in the .bore 55 ment with grooves 31 and 33, respectively, of the casing 10. A plurality of spaced, radially inwardly directed holes 45, in bushing 30, .intersecting the groove 43, connect the annular groove 31 in casing 10 with the groove 43, and similar holes 46 connect the grooves 44 and 33 of the bushing and casing, respectively. Axially intermediate holes 47 in bushing 30 align with groove 32 of the casing to provide outflow from anannular space 74 surrounding the waist of a valve 48, slidable in said'bushing.

I provide the above described bushing as a means of renewing a wearable part of the mechanism, but its inclusion is not essential to its operation. It may'be seen by inspection of the drawings that the valve 48 may be made to cooperate directly with the grooves 31 and 33 as ports.- Thus the operation of the valve would be identical as though provided with the bushing described.

The piston type valve 48 is constructed with axially spaced pistons, closely fitting the bore of bushing 30,'separated by a waist 50 .of lesser diameter co-operating with the bore of bushing 30 to form a mingling chamber 74 for the water admitted from ports 43 and 44. The spacing of the inner margins of the pistonsof said valve is indefinite relation to the spacing of the adjacent margins of grooves 43 and 44 so that, according as the axial position of said valve may be adjusted, delivery of water from either of said ports 43 or 44 maybe substantially blocked while the opposite port is widely opened or varying proportions from both'sources maybe admitted into the space '74. The valve 48 is adapted to be automatically positioned axially in the bushing by a thermostatic motor, to be described later, through a rod 52 passing through a concentric hole of said valve and having a pinned or other detachable connection therewith at the rearward end of said valve. Y

The cover 38, attached to the casing 10 as by means of screws 39 and having a suitable gasket 40 interposed between the abutting faces of said cover and easing, closes a cavity formed in said casing to form a chamber 37, in which is located a thermostatic motor. I prefer to provide the cover with a circular tongue 82 co-operating with a circular groove 83 in the casing, in which the gasket is placed, as providing means fother than the cover screws for accurately centering the cover thereon and retaining the gasket therein. Said cover has a centrallylocated, outwardly projecting boss 84 and a hole therethrough for closelyreceiving a shaft 53, rotatable therein, and means for sealing saidshaft against the escape of water thereabout, such as a conventional packing nut 54 and suitable packing.

The shaft 53 has formed at its rearward end a shallow head 59 to position outwardly against the face .of a recess formed in the cover so that the head is substantially flush therewith. The

outward end of said shaft is formed with a shoul-' der 60 adaptedto co-goperate with a face 61 of the interior of an adjusting handle 57 to position said handle axially thereon. A keyway 62 in the handle 57, andqalug on the shaft which fits slidingly in the keyway, co-operate to secure ro tation of said shaft by means'of said handle. It.

will be seen that the assembly of the shaft 53 and the handle 57, as by means of a nut 63, secures I said shaft against axial movement through the co-operation of, the face 58 of said handle with The handle 57 is in the form of a hollow bell shaped piece having its cavity adapted to cover the packing nut 54, and having a radially extending handle arm 84 for convenience of its rotation for adjustment of .the temperature of delivered water. A pointerlike projection 85-0pp0site the handle arm 84 co-operates with wording or a temperature scale on the face of the cover 38 to indicate the position of the handle. To limit the rotary movement of the handle I provide a lug 58'cast integrally with said handle and projecting from the inner face thereof so as to bring its. end ap roximately flush with the face 56, co-

operating with stop screws and 81 inserted into threaded holes provided therefor on the outer face of the cover 38. The screws 80 and 81 project outward into the path of said lug 66 and are adapted to engage said lug to stop the rotation of the handle 57.

In the embodiment of my invention the construction and arrangement of the parts is such that to deliver cold water the handle is rotated in a counterclockwise position and; conversely, for the delivery of hot water the handle is moved to the extreme clockwise position. Intermediate positions deliver water of intermediate temperatures. To provide for a limited adjustment of the maximum delivery temperature I provide a plurality of threaded holes, circumferentially spaced, for the. insertion of screw 81, see Fig. 7.

The spacing of said holes is such that-an increase of approximately ten degrees in delivery temperature may be had by inserting said stop screw in the next adjacent hole in clockwise direction.

The thermostatic motor, previously mentioned,-

a screw 65 and the shaft 53 isprovided at its rearward end with-a concentric threaded hole adapted to receive'said screw. Said screw-cooperates with said shaft as a guide to maintain and support said plate substantially parallel withthe face of the cover 38 in any axially adjusted position of said plate. Diametrically opposite holes 68 and 69, near the margin of said plate, co-operate with rearwardly. projecting pins attached to the interior face of said. cover, (one of which is shown and indicated by the numeral 69a in Fig. 3) to prevent rotation of said plate while allowing axial sliding movement thereon. Thus the rotary motion of the shaft 53 within the limits of travel provided by the handle 57 and its stops adjusts the axial position of the thermostat topredetermine the temperature of the delivered water. The brackets 70, for supporting the plurality of thermostatic stri have their upturned faces formed parallel with radii of said plate and are offset therefrom approximately half the width of said strip. The strips of thermostatic metal 67 are formed loosening the screw 71,

into spirals having a tangential outer end, the

innerend of the spiral being permanently secured to a cylindrical hub 67a. Said hubs are,

clamped to the brackets '10 by means of screws '71 passing through holes in said brackets and screwedinto threaded concentric holes in the hubs; Thus, in initially assembling the elements on the base 66 or in subsequent readjustment, by the. .hub may be rotated to bring the outer end to a definite location with respect to the base 66, and the screw 71 then tightened, locking the hub in the adiuted position.

The thermostatic strips may also have the form of a flat cantilever or may be U-shaped without impairing 'the operation or diverging from the spirit of the invention. Such arrangements are illustrated in Fig. 10 and Fig. 11 reexpansive element of the spectively.

The movable ends of the thermostaticstrips are formed to a tapering point for clearance from adjacent strips where they converge towards the center of the supporting plate 66 and are also formed with aspherical or cylindrical terminus 85 adapted to be engaged between the flangesof the bus piece 51. The thermostatic strips, whether of flat cantilever, U-shaped or spiral form, are so mounted that increase of temperature will cause the deflection of said strips rearwardly of the casing, i. e., the high thermostatic strip is on the inside ofthe spiral;

The material of the thermotaticstrips is of well known composition and comprises a plate or sheet formed of two'sheets of metal having high and low coeflicients of expansion and requires no further description. 1

For clarity of illustration the drawings show the employment of fourvsuch strips mounted as in the foregoing description but I prefer to employ a greater number of strips of thin material-preserving the radial arrangement of said strips-as giving the most sensitive construction.

The bus piece 51 comprises a short cylindrical hollow member provided with a pair of axially spaced circular flanges. Into this hollow member projects the forward end, of the connecting place therein as cralmovement or tilting shown'at 86 in Fig. 9, the holes being tapered from mentioned, and it is pinned in clearly shown in Fig. 3. The two flanges are adapted to receive therein between the termini 85 of said thermostatic'strips, also previously-described, and thereby transmit the combined deflections of said strips to the valve 48 through theinterposed rod 52.

To. eliminate all possible sources of friction, the

rod 52, previously bus piece 51 is not provided with guides; to retain it in a central position or maintain its parallelism with the plate 66 and thereforesome latof this membe through unequal action of the strips acting thereon, is anticipated and provided for in the manner of connection to valve '48 to prevent the above mentioned misalignment being transmitted to the valve and thereby causing side binding and sticking of the valve. In effect a universal joint connection between the said'parts'48 and 51 is made by forming the holes in said parts adapted to the recep i n. of said rod of considerable clearance about the'rod and positioning the pins, at opposite ends of the rod, at right angles to eachother. The holes in rod 52 are further modified to assist in freedom of movement by the construction Q both sides, thereby leaving a very narrow-bear ing-on the pins Thus the bus piece 51 may take ate corrective movement said valve, exerts no axial thrust into the chamber 3'7. The

its mean axial movement is transmitted thereto. The thermostatic motor, being supported within the chamber 3'7 and of open construction, will be practically instantly responsive to changes in.

temperature of the water mixture passing through the chamber but, owing to the distributed form of the elements of the thermostat and the progressive deflection of the elements, no separate damping of its action such as a dashpot is necessary to prevent hunting or overshooting. That is, the flow of the water through the chamber, from inlet to the outlet, is at a relatively low velocity dueto its comparatively large transverse area and thus a change of temperature of the water inflowing will affect a portion of the elements adjacent the inlet and cause a proportionof the valve before the changed temperature has affected the remainder of the elements so that the response of the thermostat, unhampered by any-damping mechanism, is immediate and proportional to the degree of temperature change. The valve48, previously described, is practically balanced in operation, that is to say, the pressure of water inflowingfrom ports 43 and 44, independently or simultaneously, and outflowing through apertures 45, whatever the positionof on the valve. Any leakage around the valve into the space provided for necessary rearward'trave'l of said valve,

is released into the chamber 37 through the annular space surrounding the valve stem 52 so that the annulus 31, through holes into the annulus 43 of bushing. 30 and into the mingling space '74 between piston ends of valve 48 and outwardly through the holes 4'7 and into the annulus 32; thence by the'passages 36a and 36 into the chamber 3'1. Similarly the cold water enters through the opening 12 from its conduit, through the passage 18, lifting ball 20, through the screen -24 into the chamber 1,6; thence through the passage 35 into the annulus 38. through holes 46 into the annulus 44 of bushing 30 and into the previously mentioned mingling space '14; thence outwardly tempered water passes 37 byway of passage 42 into paseither' discharge conduit from chamber sage 41 and thence'into which may be open, having circulated freely about 7 the thermostatic motor in chamber 37. v

The operation of the valve may be described in detail as follows: The valve being connected to sources of hot and cold water and one of the discharge valvesopened, the adjusting handle may be assumed to be turned in a clockwise direction to deliver warm water. The plate 66 is drawn forward through the rotation of screw 65, carrying with it valve 48, blocking the cold water port 44 and opening wide the hot water port 43. As the temperature of the water in the mixing chambar 37 rises, the thermostat forces the valve 48 rearwardly thereby throttling the hot water at the port 43 and admitting cold water at port 44 until the proportionate mixture attains the temperature for which the adjustment, is set. Thereafter any variation in temperature of either supply will affect the temperature of the mixture.

check ball will prevent a reverse flow of water into that conduit.

Since the primary function of the valve is to maintain the temperature of the delivered water within very close limits 3. condition may occur in which the valve would necessarily operatetocut off entirely the flow of the hotwater; as for instance, the valve being set and in use to deliver a moderately warm flow requiring a mixture of or complete loss of pressure in the cold source occurs. In order that the valve shall substantially shut off either hot or cold water it is desirable that valve 48 be a very close lit in bushing 30 as may be consistent with its free movement therein; also that said valve and bushing be of considerable hardness to withstand erosion of water at high velocities and possibly carrying abrasive sediment. Attention is directed to the coating of the co-operating surfaces of said valve and bushing with a metal of extreme hardness, such as chromium by the electroplating process.

I claim as my invention:

1. Incombination in a thermostatic valve, a casing, a rotatable shaft supported axially in said casing, a thermostat connected with said shaft, means for holding said thermostat against rotation during the rotation of said shaft, and a balanced valve connected with the thermostat, the axes of the thermostat and valve being in alignment.

2. In combination in a themostatic valve, a casing having -a pair of inlet passages, a valve controlling both passages, a shaft axially supported in said casing, a thermostat axially adjustable by rotation of said shaft and a universally jointed connection between said thermostat and said valve.

3. A thermostatic valve comprising a casing and a cover, a shaft. supported for rotation by said cover and axially positioned therein and means for limiting the rotation of said shaft to less than one revolution, an. axially adjustable thermostat, guiding means for preventing rotation thereof, an axially adjusting connection between said shaft and said thermostat and a balanced pistonvalve operatively connected to'said thermostat through a universally jointed connection.

4. In combination in a thermostatic valve, a

casing having a pair of inlet passages, a valve controlling both passages, said casing having chambers interposed between said inlet passages and said valve, and each'chamber containing a checkvalve and a screen, each of said screens prnviding lateral guidance for one of said check va ves,

5. In combination in a thermostatic valve, a casing having a pair of inlet passages and having chambers formed within the rearward or body portion of said casing adjacent said inlet passages, a check valve and a screen in each of said chambers and removable covers forsaid tially as described. chambers providing access, from the forward with said thermostat so as to be movable there- 10 with, said casing having separate chambers for the admission to the device of fluids of different temperatures and passages from said chambers hot and cold water, a considerable reduction flow of two streams of fluid to the casing, a

thermostatic device comprising a base and a plurality of radially directed thermostatic elements, means for adjustably connecting the outer end portions of said elements with said base, said 25 connecting means for each element comprising an adjustable hub carried by said .base, means for securing a bimetal strip thereto and means for securing the hub in different adjusted positions, and means for connecting the inner ends of said 3 elements with said valve member.

8. In a thermostatic valve comprising-a casing and a cover therefor, an axially adjustable thermostat, hot and cold inlets and a valve controlling both inlets; a removable valve bushing 35 comprising a hollow cylinder having axially spaced grooves on the interior thereof, a plurality of openings radial to said grooves forthe admisto regulate or cut ofi the flow of liquid, substan- 45 tially as described.

9. In combination in a thermostatic mixing valve, a casing, arotatable shaft supported in said casing, means for limiting the rotation of said shaft to less than one revolution, a thermostat 50 axially adjustable by rotation of said shaft and a balanced piston valve connected with the thermostat by means of a universally jointed connection, the axes of the valveand thermostat being in line. v

10. In a thermostatic valve having radially directed thermostatic elements; a spherical terminus for each element and a doubly flanged piece for engaging said termini," substantially as described. Y

11. In a thermostatic valve having radially directed thermostatic elements; a circular .terminusfor each element, having the axis of said terminus perpendicular to the line of motion and' parallel to the axis of the element and a doubly 65 flanged piece for engaging said termini, substanm a. BOYDSTON. 

